parser xml FEATURE add attribute to unknown xml prefix message

... and rewrite LYDXML_LOG_NAMESPACE_ERR to function.
diff --git a/tests/utests/data/test_parser_xml.c b/tests/utests/data/test_parser_xml.c
index 28c3770..d7203fa 100644
--- a/tests/utests/data/test_parser_xml.c
+++ b/tests/utests/data/test_parser_xml.c
@@ -361,7 +361,7 @@
             "  <c xmld:id=\"D\">1</c>\n"
             "</a>\n",
             LYD_XML, LYD_PARSE_OPAQ, LYD_VALIDATE_PRESENT, &tree));
-    CHECK_LOG_CTX("Unknown XML prefix \"xmld\".", "/a", 3);
+    CHECK_LOG_CTX("Unknown XML prefix \"xmld\" at attribute \"id\".", "/a", 3);
 }
 
 static void